Color photography.



UNITED STATES PATENT. OFFICE.

FREDERIG E. IVES, 0F PHILADELPHIA, PENNSYLVANIA.

. 7 COLOR PHOTOGRAPHY.

No Drawing.

T 0 all whom it may concern? 1 Be it known that I, FREDERIC EUGENE Ives.a citizen of the United States, residing at Philadelphia, in the countyof Philadelphia and State of Pennsylvania, have invented certain new anduseful Improvements in Color Photography, of whichthe following is aspecification.

This invention relates especially to color photography, although in partthe novel features hereof could be employed in other arts. Particularlythis improvement has reference to that system of color photography inwhich there are first secured two or other plu'ral number ofcolor-selection negatives bysubstantially simultaneous exposure fromsubstantially the same view-.

point, from which negatives a plurality of properly colored positivesare secured and combined, so as to reproduce fully or approximately thenatural colors of the original subject.

Within the scope of this improvement and within the art of colorphotography I intend to include the subject of motion pictures when thesame are so taken and exhibited as to reproduce the original colors ofthe subject, since the representation of motion pictures in color, forexample, on a screen, consists of a series of representations each ofwhich may be considered as composed of two or other plural number ofcolor positives suitably combined for the observer.

The present improvement has to do especially with the part of theprocess which follows the obtaining of the set of colorselectionnegatives. In other words, it relates to the problem of securing amulticolor photograph or other representation by the use of previouslysecured color-selection negatives.

Therefore, generally speaking, the object of the present improvement areto improve and simplify the obtaining from the colorselection negativesof multi-color pictures, or representations, of high and uniformquality.

The present improvement, as will be seen, proceeds in ageneral way alongthe lines of the gelatin relief system, and it is another object hereofto improve and render practical that system for the purposes of colorphotography.

Gelatin films, when treated by the bichro- Specification of LettersPatent.

Patented J une 6, 1916.

- Application filed March 13, 1915. Serial No. 14,223.

I will first describe in a general way the preferred steps contemplatedin the present improvement, and will thereafter point out in detail onemode in which the improvement may be practically carried out. i

Assuming that proper negatives have been secured, the followingprinciples for secure ing a multi-color picture may be followed: Agelatm film containing sensitive silver bromid may be employed as thestarting point. Silver bromid film is, of course, capable of beingprintedby gaslight behind the negative. Before printing, however, thefilm is to be treated by a suitable light restraining agent consistingof some temporary non-actinic medium or .dye with which the gelatin willbe impregnated. The sensitive film containing the restraining agent maybe kept in stock, as it does not deteriorate. This agent is capable ofso restraining the penetration of light as to minimize its action uponthe sensitive silver salt. Without such restraint the full action of thelight would result, as will be hereinafter explained, in an extremelyhigh, contrasting and unsatisfactory relief. The film, which may haveits support upon glass, celluloid, or the like, containing the silverbromid and the temporary light restrainer, as stated, will now beexposed behind the negative and. preferably through the rear glass orcelluloid base, so as to avoid any need of stripping or transferring insubsequent processes.

After such exposure, by artificial light, the film will be put throughthe following steps or treatment, in which the temporary lightrestrainer will be automatically removed. The exposed film will betreated by the usual methods for developing the silver image. Suchdevelopment, if properly carried out, does not affect the condition ofthe gelatin. Gelatin, however, in the presence of silver, has. thecharacteristic that it may be ren- Q 1,1se,ooo

dered insoluble by certain agents, which I will term desolublizingagents. This treatment selectively desolublizes the gelatin according tothe silver image. Such step may be followed by washing or developing thegelatin in hot water, this serving to remove from the face of the filmall of the gelatin which 'is not in intimate contact with reducedsilver. There results a tenuous gela= tin relief. This relief may berendered transparent by dissolving out of the silver image by usualmethods. Having thus obtained from-each of the negatives an extremelytenuous, delicate and accurate gelatin positive relief of the image, theseveral reliefs may be employed to create color images by selectiveabsorption of color, for example, by immersing in water-soluble dye ofthe proper colors. Having the several color images, they may be combinedin any suitable manner to produce the final picture or representation.For example, the reliefs may be bodily superposed to build up a colorphotograph. Orthe several dyed reliefs may be employed simply ascarriers,

each in turn being caused to give up its color image by imbibition intoa common print member, thus again combining the colors into the finishedpicture. For color motion pictures any one of these systems of combiningmay be utilized.

In detail the following may be the procedure for carrying out thepresent process.

The negatz'oes.As before stated, the negatives may be procured in anydesired manner, for example, by means of the cameras or apparatusdisclosed in prior Patent Number 980,961 of January 10, 1911. Forconvenience I will assume the three-color system, although it is obviousthat the present improvements could be employed in connection with thetwo-color, four-color or, other system. Assuming the three-color system,each of the three negatives will represent one of the so-called primarycolors, red, green and blue. The corresponding complementary orsecondary or printing colors will be respectively peacock (bluegreen),magenta (or pink) and yellow.

The gelatin fiZm-.-".The gelatin film could be a uniform layer ofgelatin upon a substantially transparent support, such as glass orcelluloid. In referring to gelatin I intend to include equivalentmaterials such as the other well-known colloids. There is a marketedsensitive film known as cinematograph positive film consisting of athin, flexible, celluloid base, coated with gelatin containing veryfine-grained silver bromid, which is adapted to serve the purposeshereof. If such film be employed, however, without restraining theaction of light, its use would be unsatisfactory. The. silver image willdevelop to such an extent through the thickness of the gelatin film withan avfectly meet the specified requirements.

erage photographic negative that the gelatin in the subsequentdesolublizing process will become insoluble practically throughout its.thickness in 'the shadows of the image before the exposure ordevelopment has been carried far enough to insure retaining the detailsin the lightshades of the picture, so that the resulting relief printswould be far too strong, contrasty and inaccurate for practical use incarrying out the present method. The coloring of the gelatin film with atemporary light restrainer is calculated to meet this difficulty. Alight absorbing agent will be suitable which is adapted to oppose deeppenetration of light, if such agent is substantially inert chemicallyand mechanically with respect both to the gelatin and to the silverbromid, and capable of being discharged in the subsequent developing orwashing processes. The depth of penetration is slight over the wholeimage,

and proportional to the intensity of the light. Such light restrainingagent is preferably a water-soluble dye of a color capable ofeffectively absorbing all of the light rays to which the silver bromidis most sensitive. For an ordinary sensitive film, which is particularlysensitiveto blue-violet rays, and

not rendered sensitive to green or red, a suitable agent is tartrazindye. This is a soluble dye of a yellow color. 3.2 grams dissolved in oneliter of water will very persensitive film should be immersed in the dyesufficiently to deeply stain or color the gelatin. Three minutesimmersion should be sufiicient, followed by draining and drying. It willbe understood that, as the tartrazin dye does not injure the gelatin orsilver bromid or deteriorate the films, it may be in troduced in theemulsion, or subsequently, in the process of manufacture, and the'dyedfilms kept in stock, so that the photographer is relieved of thenecessity of performing this step. If a film should be employed whichhas been rendered sensitive to red or green or other special colors, thetartrazin dye would not suflice, but some other dye would need to beselected capable of absorbing whatever kinds of light the films weresensitive to, without reacting to destroy either the primaryblue-sensitiveness of the film or the special green or red or othersensitiveness which had been added by special treatment (with special.color sensitizing dyes).

Eaeposure.The sensitized and dyed film is to be exposed behind thenegative. Since in the subsequent operation of dissolving out theunaffected gelatin the washing is done at the face, it is necessary toeffect the exposure through the rear or transparent .base of the film.The very deep temporary The or portion of the gelatin adjacent to theglass or'celluloid support. By this arrangement the silver image will beconfined wlthin such thin layer next to the base,and, consequently, inproducing the rehef much the greater part of the original gelatin Wlllbe washed away.

Development of silver image.After proper exposure the silver image is tobe developed in any usual manner, which will not desolublize thegelatin. For example, ordinary metol-hydroquinone developer may beemployed. This step should befollowed by very thorough rinsing andwashing, so as to remove any tracesof sulfites or other active salts.These steps of develop ng and washing serve also to remove the temporarylight restrainer or water-soluble dye. The gelatin, however, is stillunafiected and consists of a layer of uniform thickness containing arather thin silver image confined closely to the portion of the gelatinlayer which is next to the transparent support.

Desolublizing the gelatin.This step consists in rendering insoluble allparts of the gelatin which are in intimate contact wlth the reducedsilver. It is a fact that such desolublizing can be effected bytreatment with certain agents, for example, the followingbichromate-bromid solution: am, monium bichromate, 6.8 grams; potassiumbromid, 6.8 grams; sulfuric acid, 6.5 cubic centimeters; water, 1 liter.Upon immersing the film in this solution the desolubl zing actionproceeds as stated. The portions of the gelatin which are not inintlmate contact with reduced silver remain unaffected, and thereforesoluble in hot water, whereas the portions which contain the silver areselectively rendered insoluble in degrees according with the lights andshades of the silver image.

The presence of the sulfuric acid inthe above desolublizing bath is ofadvantage in that, as the action of the bath proceeds, the reducedsilver is bleached and under the dark-room lantern it is, therefore,possible to easily determine the completion of the action by thecompletely bleached condition of the silver image.

Deoelopment of gelatin relief-After rinsing the desolublized film incold water, it only remains to bathe it in hot water to develop thegelatin relief by dissolving out the unaffected soluble gelatin. Asstated, by far the major portion of gelatin is thus removed, leavingonly an extremely tenuous layer or relief of insoluble gelatin, carriedon the transparent base and preserving in full the variations of lightand shade constituting the image. now remove the silver, which hasserved its purpose, and this may be eifected in any ordinary manner, forexample, by transferring to a bath of sodium hyposulfite or It ispreferred to visible or inappreciable relief. To redevelop or producethe image, it is only necessary to immerse each such relief in a dyebath of suitable color. Thus, the relief made from the negative producedby a green screen in the camera or a sensitiveness to green rays shouldbe dyed the complementary color, magenta, and similarly with theremaining reliefs.

Combining the monochrome images.- Having the three reliefs dyedrespectively magenta, peacock and yellow, they may be combined by bodilysuperposing them and mounting them, for example, upon a White back, thusgiving a color photograph which may be handled as an ordinaryphotograph; or, successively, the three color images might betransferred by imbibition into a single gelatin layer upon paper; orother modes of combining them might be employed.

The importance of securing tenuity in the reliefs is great, but will notbe attempted to be fully elucidated here. Such imperceptible lowness ofrelief not only insures the greatest accuracy in color gradations andquicknessand completeness of the staining operation, but yields acertain delicacy and brilliance of coloring, which is peculiarlynecessary in building up froma plurality of monochromes a colorphotograph to be seen by reflected light. Any variation in color orgradations in any one of the monochromes does not merely affect thetrueness ,of that monochrome, but destroys the effect It is obvious thatin producing color photographs by the method of this application, themethod may be employed throughout for all of the. monochromes, or, onthe other hand, may be only partially employed, since part of themonochromes might be made b other processes and combined with that orthose produced by the present process.

Coloring of the separate monoohromes. Whilea worker skilled in the artwould be able to select the'proper coloring-materials for the threeseparate monochromes afterward to be combined, I would mention suitablematerials for this purpose. For giving a peacock bluecolor to the reliefmade from the red selection negative may be used Bayers alizarin blu'e AS. For giving a magenta color to the relief made from the parts ofBayers alizarin rubinol R and rubinol 3. For giving a yellow color tothe relief made from the blue selection negative may be used Bayerssulfon yellow B. It may, however, be desirable to produce one of thethree components directly upon a paper backing, so that, when the othertwo color images are combined therewith by superposition, imbibition, orotherwise, the color photograph will be complete, backing and all. Ithas heretofore been proposed to positive prints into a peacock color.

employ an ordinary ferricyanid or blueprint for a basic monochrome ofpeacock color, but, as this requires daylight and is subject to thevariations and delay thereof,

it is preferable to employ a method capable of use with artificiallight. I have devised such a method which operates on the principle ofconverting ordinary silver bro%lid 1e following procedure devised by meproduces with certainty extremely clear and brilliant peacock prints,and provides all desirable control both of density and contrast. Afteran ordinary bromid print has been well washed to remove the fixingagents, it is to be immersed in the following solution, freshlyprepared, for from three to six minutes with constant rocking of thetray: 10% potassium ferricyanid 7 cu. cm.; 10% No. 8 acetic acid,'1l0cu. cm.; 10% ferric ammonium citrate (brown), 7 cu. cm.; 10%

hydrochloric acid, 1 to 3 cu. cm., according to the degree of contrastand brilliance required. This effects the toning of the print to a deep,heavy blue with the whites considerably tinted. The print is then washedin water and transferred to such an alkaline fixing bath as thefollowing: Sodium hyposulfite, .25 kilogram; sodium bicarbonate, 16grams; water, 1 liter. The print will then be agitated in this fixingbath until the whites have perfectly cleared and the shadow detailsbecome perfectly differentiated. It will then be rinsed in water andplaced for a few seconds in a solution of an acid, preferably a strongsolution of oxalic acid, and afterward finally washed again in athorough manner, drained and dried. This completes the production of thepeacock blue print on paper. The employment ofacid toning bath, inconnection with the subsequent steps of clearing by means of an alkalibath, and finally fixing in an acid bath, is believed to be of criticalimportance in meeting the necessity for securing clean, brilliantprints, with control of contrasts.

I believe I am the first to propose a photographic printing processcomprising the incorporation, with the sensitive silver salt in asuitable film, of an actinic-light restrainer, whereby, upon exposureand development, the silver image will be confined to one side of thefilm. I also believe I am the first to propose a method of producing aphotographic colloid relief print comprising the steps of incorporatingin a suitably supported colloid layer witha sensitive silver salt anactinic-light restraining agent, exposing and developing the silverimage, desolublizing the colloid by a suitable agent under the selectivecontrol of the silver image, and dissolving away the soluble colloid,whether or not the other and subsequent preferred steps before describedbe employed. The subsequent preferred step of dissolving out the silverimage might in some cases be dispensed with, for example, if the colloidprint is to be used merely as a temporary means of absorbing andcarrying a color image intended to be transferred by imbibition to acolor photograph. The subsequent preferred step of selectively coloringthe colloid print might be dispensed with, if some equivalent besubstituted, such, for example, as the pre-colo'ring thereof. Thefullest embodiment, however, of the present invention requires theperformance of all of the preferred steps mentioned in this paragraph,for the purposes of producmg multi-color pictures in the art of colorphotography. 7

It will thus be seen that I have described a process, with all necessarydetails, embodymg the prlnciples and attaining the objects and.advantages of this invention. Since many matters of treatment,manipulation, selectlon and proportion of ingredients, successlon ofsteps, and other details may be variously modified without departingfrom theprinciples involved, I do not intend any limltation to suchdetails excepting, so far as set forth in the appended claims.

l/Vhat is claimed is:

1. In the art of color photography the method of producing a multi-colorpicture from a set of color-selection negatives, comprlsing the steps ofincorporating in a suitably supported colloid layer with a sensitivesilver salt an actinic-light restraining agent, exposing the samebeneath one of the negatives, developing the silver image, desolublizingthe colloid by a suitable agent under the selective control of thesilver lmage, and subsequently selectively coloring the colloid andcombining the color image thus produced with color images produced fromthe remaining negatives.

2. In the art of color photo raphy the method of producing a multi-co orpicture from a set of color-selection negatives, comprising the steps ofincorporating in a suitably supported colloid layer with a sensitivesilver salt an actinic-light restraining agent consisting of an inertwater-soluble dye of a color non-actinic to the silver salt, exposingthe same beneath one of the negatives, developing the silver image,desolublizing the colloid by a suitable agent under the selectivecontrol of the silver image, and sub- 1,1se,ooo

sequently selectively coloring the colloid and combining the color imagethus produced with color images produced from the remaining negatives.

3. In the art of color photography method of producing a multi-colorpicture from a set of color-selection negatives, comprising the steps ofincorporating in a suitably supported colloid layer with a sensitivesilver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, desolublizingthecolloid by a suitable agent under the selective control of the silverimage, said agent, consisting of a bichromate plus a bromid acidified toeffect bleachin of the reduced silver, and subsequently se ectivelycoloring the colloid and combiningthe color image thus produced withcolor images produced from the remaining negatives.

7.4. In the art of color photography the method of producing amulti-color picture from a set of color-selection negatives, comprisingthe steps of incorporating in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing thesame beneath one of the negatives, developing. the silver image,desolublizing the colloid by a suitable agent under the selectivecontrol of the silver image, dissolving out the undesolublized gelatinto leave a tenuous relief, and combining a color image produced in suchrelief with color images produced from the remaining negatives.

5. In the art of color photography the method of producing a multi-colorpicture from a set of color-selection negatives, comprising the steps'ofincorporating in a suitably supported colloid layer with a sensitivesilver salt an actinic-light restraining agent, exposing the samebeneath one of the negatives and through the transparent support of thecolloid so that the restraint of light confines its action to the sideof the colloid layer next to its support, developing the silver image,desolublizing the colloid by a suitable agentunder the selective controlof the silver image, dissolving out the undesolublized gelatin to leavea tenuous relief, and combining a color image produced in such reliefwith color images produced from. the remaining negatives.

6. In the art of color photography the from a set of color-selectionnegatives, comprising the steps of incorporating in a suitably supportedcolloid layer with a sensitive silver salt an actinic-light restrainingagent consisting of an inert water-soluble dye of a color non-actinio'tothe silver salt, exposing the same beneath one of the negatives andthrough .the transparent support of the colloid so that the restraint oflight confines its action to the side of the colloid layer next I theimage, dissolving out the undesolublized 'gelatin to leave a tenuousrelief, and com- .bining a color image produced in such relief withcolor images produced from the remaining negatives.

7. In the art of color photography the method of producing a multi-colorpicture froma set of color-selection negatives, comprising the steps ofincorporating in a suitably supported colloid layer with a-sensitivesilver salt an actinic-light restraining agent, exposing the samebeneath one of the negatives, developing the silver image, desolublizingthe colloid by a suitable agent under the selective control of thesilver image, dissolving out the silver image, and subsequentlyselectively coloring the colloid and combining the color image thusproduced with color images produced from. the remaining negatives.

8. In the art of color photography the method of producing amulti-ecolor picture from a set of color-selection negatives, com-vprising the steps of incorporating in a suitably supported colloid layerwith a sensitive silver salt an actinic-light restraining agent,exposing the same beneath one of the negatives, developing the silverimage, de: solublizing the colloid by a suitable agent under theselective control of the silver image, dissolving out the silver image,dissolving out the undesolublized gelatin to leave a tenuous relief, andcombining a color image produced in such relief with-color imagesproduced from the remaining negatives.

9. In the art of color photography the method of producing a multi-colorpicture from aset of color-selection negatives, comprising the steps ofincorporating in a suitably supported colloid layer with a sensitivesilver salt an actinic-light restraining agent, exposing the samebeneath one of the negatives, developing the silver image, desolublizingthe colloid by a suitable agent under the selective control of thesilver image, dissolving out the silver image, dissolving out theundesolublized gelatin to leave a tenuous relief, and combining the samein colored condition with color images produced from the remainingnegatives by superposmethod of producmg a multi-color picture ing suchcolored relief bodily with the other portion of the picture.

10. In the art of color photography the method of producing amulti-color picture from a set of color-selection negatives, comprisingthe steps of incorporating in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing thesame beneath one of the negatives, developing the silver image,desolublizing the colloid by a suitable agentunder scribed.

11. In the art of color photography the improvement in makingmulti-color pictures from a set of color-selection negatives, whichconsists in producing colloid reliefs from one or more of such negativesby impregnating a sensitive gelatin silver bromid film with a suitabletemporary actinic-light restraining agent, exposing such film behind thenegative and through its rear or base, developing thesilver image by anysuitable method, selectively desolublizing the gelatin by a suitabledesolublizing agent which operates in the presence of reduced silver,and dissolving out the silver image and the soluble gelatin, thusaffording a gelatin relief; coloring each of such reliefs byselect'ive'absorption of dye of the corresponding color, so as toproduce monochrome color images, and, finally, suitably combining themonochrome color images produced from all of said set of negatives intoa single multi-color picture.

12-. The method of producing a photographic colloid print comprising thesteps of incorporating in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing anddeveloping the silver image, and desolublizing the colloid by a suitableagent under the selective control of the silver image.

13. The method of producing a photographic colloid print comprising thesteps of incorporating. in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing anddeveloping the silver image, desolublizing the colloid by a suitableagent under the se lective control of the silver image, and dissolvingout the undesolublized colloid.

14. The method of producing a photographic colloid print comprising thesteps of" incorporating in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing anddeveloping the silver image, desolublizing the colloid by a suitableagent under the se lective control of the silver image, and dissolvingout the silver image.

15. The method of producing a photographic colloid print comprising thesteps of incorporating in a suitably supported colloid layer with asensitive silver salt an actinic-light restraining agent, exposing anddeveloping the silver image, desolublizing the colloid by a suitableagent under the selective control of the silver image, and dissolvingout the silver image and the undesolublized colloid. V

16. Method of producing tenuous colloid relief prints which consists inimpregnating a sensitive gelatin silver bromid film with a suitabletemporary actinic light restraining agent, exposing such film behind anegative and through its rear or base, developing the silver image byany suitable method, select-ively desolublizing the gelatin by asuitable solublizing agent which operates in the presence of reducedsilver, developing in hot water to remove the soluble gelatin, thusaffording a gelatin relief.

In testimony whereof, I have affixed my signature in presence of twowitnesses.

FREDERIG E. IVES. Witnesses:

FIRED C. MARTIN, ALFRED THOMPSON.

